Babies who weigh less than 1,500 grams at birth have their brain development affected, according to the results of a study published in the medical journal NeuroImage. Every year, one in ten babies in the world is born prematurely. When children are born too early, they are at higher risk for physical and mental disabilities.
Researchers from the Norwegian University of Science and Technology (NTNU), conducted a study to better understand the consequences of very low birth weight on cognitive development.
To investigate this question, the researchers relied on a group of very low birth weight individuals born between 1986 and 1988 in Trondheim, Norway. These people had participated in studies when they were 1, 5, 14 and 20 years old. Thirty-two people aged 22 to 24 from this group participated in this new study and were matched with controls of the same age with normal birth weight.
For the first time, researchers used fMRI (functional imaging) imaging to see activation in different parts of the brain when subjects were engaged in a task.
In this study, participants looked at a computer screen and saw a series of random letters. Their task was to press a button as quickly as possible when they saw a new letter appear, except when the letter was “x”. The most frequent response was to press the button, as the letter “x” was only presented 10% of the time.
“You need two types of cognitive control to accomplish this task,” said Alexander Olsen, associate professor at the Norwegian University of Science and Technology (NTNU). “So this simple task gave us a lot of information.”
The brain is constantly working to create meaning from the flow of information that reaches us every minute of our day. Researchers have identified two different processes that the brain relies on to accomplish this task: a proactive cognitive control function and a reactive function.
Proactive cognitive control is about working proactively on a task. Participants knew that most of the time they had to press the button, and they proactively prepared themselves mentally to identify new letters to respond as quickly and accurately as possible.
But the appearance of the “x” on the screen demanded a different reaction. The reactive system kicks in when something happens that is not expected. You have to adapt your behavior and react to the new information, to come up with a new plan. “
Premature babies use their brains in different ways
The results of the study showed that premature participants completed tasks like everyone else, but they used different cognitive functions to do so.
“What we found was that the premature group had less proactive but more responsive brain activation compared to the normal birth weight control group,” the researcher said.
This hyper-reactive brain activation signature was accompanied by poor organization of white matter in the brain and was associated with intelligence and anxiety disorders.
“Their brains were reacting as if they encountered something new every time,” he explained. “This suggests that their brain is hypervigilant due to a suboptimal organization of the central nervous system. They are less prepared and more surprised each time, which could create more anxiety issues. “
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